A buffer conveyor comprises a drivable endless conveyor belt which successively follows a transport path from an input station to an output station and a return path. A frame includes two parallel transport path frame legs and a U-shaped transport path bridge. The transport path bridge includes a curved bridge portion and parallel bridge legs extending therefrom. Each transport path frame leg is provided with a transport path frame guide for a lateral contact side of the belt in outward direction as seen from the other frame leg. The transport path bridge is shaped such that along the curved bridge portion and respective twisted regions of the bridge legs adjacent to the curved bridge portion the belt has a transverse down-slope towards the inside of the U-shape and such that the lateral contact side (of the belt at said twisted regions is above the respective transport path frame guides.